It depends how $\delta$ and $k$ approach their respective limits. If $\delta=\frac ck$ then the limit is $e^{ac}$.
–
Hagen von EitzenSep 29 '12 at 22:36

It is undefined, depends on how $\delta$ and $k$ are behaving with respect to each other. The path $\delta=1/n$, $k=n$ gives a different result than $\delta=1/n$, $k=2n$. Almost anything can happen.
–
André NicolasSep 29 '12 at 22:36